scholarly journals Nucleic Acids — The Use of Nucleic Acid Testing in Molecular Diagnostics

Author(s):  
Gabrielle Heilek
2019 ◽  
Vol 116 (33) ◽  
pp. 16240-16249 ◽  
Author(s):  
Wei Ouyang ◽  
Jongyoon Han

Rapid and reliable detection of ultralow-abundance nucleic acids and proteins in complex biological media may greatly advance clinical diagnostics and biotechnology development. Currently, nucleic acid tests rely on enzymatic processes for target amplification (e.g., PCR), which have many inherent issues restricting their implementation in diagnostics. On the other hand, there exist no protein amplification techniques, greatly limiting the development of protein-based diagnosis. We report a universal biomolecule enrichment technique termed hierarchical nanofluidic molecular enrichment system (HOLMES) for amplification-free molecular diagnostics using massively paralleled and hierarchically cascaded nanofluidic concentrators. HOLMES achieves billion-fold enrichment of both nucleic acids and proteins within 30 min, which not only overcomes many inherent issues of nucleic acid amplification but also provides unprecedented enrichment performance for protein analysis. HOLMES features the ability to selectively enrich target biomolecules and simultaneously deplete nontargets directly in complex crude samples, thereby enormously enhancing the signal-to-noise ratio of detection. We demonstrate the direct detection of attomolar nucleic acids in urine and serum within 35 min and HIV p24 protein in serum within 60 min. The performance of HOLMES is comparable to that of nucleic acid amplification tests and near million-fold improvement over standard enzyme-linked immunosorbent assay (ELISA) for protein detection, being much simpler and faster in both applications. We additionally measured human cardiac troponin I protein in 9 human plasma samples, and showed excellent agreement with ELISA and detection below the limit of ELISA. HOLMES is in an unparalleled position to unleash the potential of protein-based diagnosis.


2021 ◽  
Author(s):  
hongyu liu ◽  
Yuhao You ◽  
Youzhuo Zhu ◽  
Heng Zheng

Detection of nucleic acids have become significantly important in molecular diagnostics, genetics therapy, mutation analysis, forensic investigations and biomedical development, and so on. In recent years, exonuclease Ⅲ (Exo III)...


Author(s):  
Dimitrij Lang

The success of the protein monolayer technique for electron microscopy of individual DNA molecules is based on the prevention of aggregation and orientation of the molecules during drying on specimen grids. DNA adsorbs first to a surface-denatured, insoluble cytochrome c monolayer which is then transferred to grids, without major distortion, by touching. Fig. 1 shows three basic procedures which, modified or not, permit the study of various important properties of nucleic acids, either in concert with other methods or exclusively:1) Molecular weights relative to DNA standards as well as number distributions of molecular weights can be obtained from contour length measurements with a sample standard deviation between 1 and 4%.


Author(s):  
Stephen D. Jett

The electrophoresis gel mobility shift assay is a popular method for the study of protein-nucleic acid interactions. The binding of proteins to DNA is characterized by a reduction in the electrophoretic mobility of the nucleic acid. Binding affinity, stoichiometry, and kinetics can be obtained from such assays; however, it is often desirable to image the various species in the gel bands using TEM. Present methods for isolation of nucleoproteins from gel bands are inefficient and often destroy the native structure of the complexes. We have developed a technique, called “snapshot blotting,” by which nucleic acids and nucleoprotein complexes in electrophoresis gels can be electrophoretically transferred directly onto carbon-coated grids for TEM imaging.


2021 ◽  
Vol 23 (1) ◽  
pp. 219-228
Author(s):  
Nabanita Saikia ◽  
Mohamed Taha ◽  
Ravindra Pandey

The rational design of self-assembled nanobio-molecular hybrids of peptide nucleic acids with single-wall nanotubes rely on understanding how biomolecules recognize and mediate intermolecular interactions with the nanomaterial's surface.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evan Amalfitano ◽  
Margot Karlikow ◽  
Masoud Norouzi ◽  
Katariina Jaenes ◽  
Seray Cicek ◽  
...  

AbstractRecent advances in cell-free synthetic biology have given rise to gene circuit-based sensors with the potential to provide decentralized and low-cost molecular diagnostics. However, it remains a challenge to deliver this sensing capacity into the hands of users in a practical manner. Here, we leverage the glucose meter, one of the most widely available point-of-care sensing devices, to serve as a universal reader for these decentralized diagnostics. We describe a molecular translator that can convert the activation of conventional gene circuit-based sensors into a glucose output that can be read by off-the-shelf glucose meters. We show the development of new glucogenic reporter systems, multiplexed reporter outputs and detection of nucleic acid targets down to the low attomolar range. Using this glucose-meter interface, we demonstrate the detection of a small-molecule analyte; sample-to-result diagnostics for typhoid, paratyphoid A/B; and show the potential for pandemic response with nucleic acid sensors for SARS-CoV-2.


Author(s):  
Dustin E Bosch ◽  
Patrick C Mathias ◽  
Niklas Krumm ◽  
Andrew Bryan ◽  
Ferric C Fang ◽  
...  

Abstract Background An elevated white blood cell count (>15 thousand/μL) is an established prognostic marker in patients with Clostridium difficile infection (CDI). Small observational studies have suggested that a markedly elevated WBC should prompt consideration of CDI. However, there is limited evidence correlating WBC elevation with the results of C. difficile nucleic acid testing (NAAT). Methods Retrospective review of laboratory testing, outcomes, and treatment of 16,568 consecutive patients presenting to 4 hospitals over four years with NAAT and WBC testing on the same day. Results No significant relationship between C. difficile NAAT results and concurrent WBC in the inpatient setting was observed. Although an elevated WBC did predict NAAT results in the outpatient and emergency department populations (p<0.001), accuracy was poor, with receiver-operator areas under the curve of 0.59 and 0.56. An elevated WBC (>15 thousand/μL) in CDI was associated with a longer median hospital length of stay (15.5 vs. 11.0 days, p<0.01), consistent with leukocytosis as a prognostic marker in CDI. NAAT-positive inpatients with elevated WBC were more likely to be treated with metronidazole and/or vancomycin (relative ratio 1.2, 95% confidence interval 1.1–1.3) and die in the hospital (relative ratio 2.9, 95% CI 2.0–4.3). Conclusions Although WBC is an important prognostic indicator in patients with CDI, an isolated WBC elevation has low sensitivity and specificity as a predictor of fecal C. difficile NAAT positivity in the inpatient setting. A high or rising WBC in isolation is not a sufficient indication for CDI testing.


The Analyst ◽  
2021 ◽  
Author(s):  
Qingteng Lai ◽  
Wei Chen ◽  
Yanke Zhang ◽  
Zheng-Chun Liu

Peptide nucleic acids (PNAs) have attracted tremendous interest in the fabrication of highly sensitive electrochemical nucleic acid biosensor due to their higher stability and increased sensitivity than common DNA probes....


2021 ◽  
Author(s):  
Zhongjie Li ◽  
Fengfeng Liu ◽  
Jinzhao Cui ◽  
Zhibin Peng ◽  
Zhaorui Chang ◽  
...  

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